From the early years of the Twentieth Century to the closing days of the Roaring Twenties, the pneumatic player piano was the most important medium of home entertainment. At a time when there were no radios, no television, and the closest thing to a hi-fi was a phonograph which was barely capable of reproducing music, the player piano was a truly marvelous instrument.
The conventional 88 note upright player piano utilizes vacuum as its motive power. The vacuum is created by "pumping" footpedals which operate suction bellows in the lower portion of the piano. The vacuum is channeled to (1) an air motor in the upper portion of the piano which functions to drive the paper roll over the tracker bar, and (2) a pneumatic stack which typically includes a common vacuum manifold and a separate diaphram, valve and bellows for each of the 88 notes. When a perforation in the paper roll passes over a hole in the tracker bar, air is admitted so as to deflect the associated diaphram (called a pouch) in the pneumatic stack. When a particular pouch is deflected, it lifts one of the 88 valves from its lower seat on the vacuum manifold to an upper seat which closes off the atmosphere and reduces the pressure in one of the 88 bellows. Each bellows is mechanically coupled to a different note which is struck by the collapsing bellows. After the perforation passes from the tracker bar the vacuum on both sides of the pouch is equalized by a small hole called the bleed. Atmospheric pressure on the valve causes it to return to its original position (lower seat on the vacuum manifold) thus removing the vacuum from the bellows.
Although the player piano, as a source of music, has been replaced by radio and modern Hi-Fidelity equipment, it is making a comeback as an entertainment center for family get togethers. When it comes to just plain fun and nostalgia the player piano is simply unequalled. An important reason for this lies in the fact that there is an interactive relationship between the human and the machine. The crowd can sing along with their favorite tunes, the pumper can vary the tempo as desired, or add expression by varying the pedalling force.
The traditional player action occupied a large volume within the piano case. It is therefore not possible to incorporate a conventional player action in a modern small case spinet piano. In addition to its bulkiness, many of the early player actions were difficult to pump - particularly for long periods. A further shortcoming of many early player piano mechanisms was due to the large vacuum reserve which was required for smooth operation of the air motors and pneumatics. The large reserve resulted in a long time constant for the vacuum system with a consequent decrease in the expression capabilities. Furthermore, from the standpoint of duplicating the traditional player piano actions, there is the additional factor posed by the tremendous increase in the cost of labor. What is actually desired is a high quality player piano action which can be inexpensively built and easily installed within the confines of a conventional spinet case without serious modification of the overall dimensions or appearance.
Accordingly, a primary object of the present invention is to provide an inexpensive player piano action which can be easily installed within the confines of a conventional modern spinet piano case without serious modification thereof.
A further object of one aspect of the present invention is to provide a pneumatic player piano having an electric roll drive.
A further object of one aspect of the present invention is to provide an arrangement for controlling an electric roll drive so as to simulate a conventional air motor drive.
A further object of one aspect of the present invention is to provide a minimum effort pneumatic player piano action.
A further object of one aspect of the present invention is to provide a pneumatic player piano which will rapidly respond to changes in pedal pressure.
A further object of one aspect of the present invention is to provide an improved pneumatic stack which can be largely fabricated using modern molding technology.
A further object of one aspect of the present invention is to provide a simple inexpensive pneumatic valve.
A further object of one aspect of the present invention is to provide an improved system for loading the take-up spool to effect roll tracking.
Other objects and advantages of the present invention will be obvious from the detailed description of a preferred embodiment given herein below.